Lean planning and control: Principles and practice

A basic characteristic of lean, agile, and responsive production systems are the use of teams instead of functional departments. Another characteristic is the use of rather simple shop floor control methods to manage the flow of orders. The shop floor control methods provide robust and visual control to cope with the dynamic situations at the shop floor, such as variation in processing times, routing sequences, disturbances, resource allocation, et cetera. Although the main focus of lean is to eliminate unnecessary variation that causes waste, unreasonableness, and unevenness, there will be variation that might be considered to be necessary, valuable, or unavoidable. This type of variation is directly concerned with providing customer value and hence needs to be accommodated in the control system. This paper investigates what fundamental principles are behind lean planning and control methods and how they can be applied in practice. We describe underlying principles that have been developed even before computerized methods such as Material Requirements Planning and Input/Output control became popular. Next we review some recent developments in the use of lean planning and control methods, such as Polca, (M)Conwip, and Cobacabana. We provide several short cases of practical applications to illustrate these concepts.